Since the issuance of U.S. Pat. No. 1,530,852 to Arthur H. Pitney, Mar. 24, 1925, the postage meter has had a steady evolution. Postage meters are mass produced devices for printing a defined unit value for governmental or private carrier delivery of parcels and envelopes. The term postage meter also includes other like devices which provide unit value printing such as a tax stamp meter. Postage meters include internal accounting devices which account for postage value, which postage value is stored within the meter. The accounting device accounts for both the recharging of the meter with additional postage value and the printing of postage by the meter printing mechanism. No external independent accounting system is available for accounting for the postage printed by the meter. Accordingly, postage meters must possess high reliability to avoid the loss of user or governmental funds.
Throughout the years, two general types of postage meters have been used: one that uses a rotatable print drum and is referred to as a rotary postage meter, and the other that uses a stationary print head and a reciprocating platen and is referred to as a flat bed postage meter. Most recently, there has been a change from a completely mechanical device to meters that incorporate electronic components extensively. Although there have been a number of changes, there are certain elements that remain constant. For example, the need for security is absolute. In prior postage meters, such security is applied both to the printing portion of the meter and to the accounting portion. The reason for the absolute security requirement is because a postage meter is printing value, and unless security measures are taken, one would be able to print unauthorized postage, thereby defrauding the U.S. Postal Service. Most security measures taken are of a physical nature, but recently there have been suggestions for the use of encryption to ensure that a postage indicia is valid. Nevertheless, such encryption merely supplements the physical security systems that have been used and suggested by the prior art. Furthermore, the known prior encryption systems attest to the validity of the indicia but provide no means for determining whether the printed indicia is just a copy of a valid indicia. Additionally, prior systems relied upon the post office accounting for postage by monitoring the number and value of mail pieces sent by a particular meter user.
Another common factor in prior postage systems is the inclusion of a postage indicia normally placed in the upper right hand corner of one surface of an envelope or package. This indicia has taken a specific form. The postage amount is contained in a rectangular border and the date of the postage impression appears in a circular border. This form has evolved from the original appearance of a canceled stamp wherein the stamp is of a rectangular configuration and the cancellation mark included the date within a circle. Also included in this indicia is the postage meter number and the city and state from which the envelope was mailed.
Although postage meters have performed satisfactorily in the past and continue to perform satisfactorily, with the advance of electronics, postage systems are needed that are less expensive and more flexible while still providing the serviceability and security required. Additionally, it would be desirable to have a postage system that is more compatible with contemporary mail processing systems.